# std::reference_wrapper<T>::reference_wrapper

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< cpp‎ | utility‎ | functional‎ | reference wrapper

template< class U > reference_wrapper( U&& x ) noexcept(/*see below*/) ; | (1) | (since C++11) (constexpr since C++20)
reference_wrapper( const reference_wrapper& other ) noexcept; | (2) | (since C++11) (constexpr since C++20)

Constructs a new reference wrapper.

1) Converts x to `T&` as if by T& t = std::forward<U>(x);, then stores a reference to `t`. This overload participates in overload resolution only if typename std::decay<U>::type is not the same type as `reference_wrapper` and the expression FUN(std::declval<U>()) is well-formed, where `FUN` names the set of imaginary functions

    void FUN(T&) noexcept;
    void FUN(T&&) = delete;

2) Copy constructor. Stores a reference to other.get().

### Parameters

x | - | an object to wrap
other | - | another reference wrapper

### Exceptions

1)
`noexcept` specification:
noexcept(noexcept(FUN(std::declval<U>())))
where `FUN` is the set of imaginary functions described in the description above.

### Example

| This section is incomplete Reason: no example

### Defect reports

The following behavior-changing defect reports were applied retroactively to previously published C++ standards.

DR | Applied to | Behavior as published | Correct behavior
--- | --- | --- | ---
LWG 2993 | C++11 | deleted `reference_wrapper(T&&)` constructor interferes with overload resolution in some cases | replaced with a constructor template

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